I would think something difficult like engineering would be closer to 5 years. Reason being that not everyone is prepared for such a program (you need to start your first semester in calculus and physics or you will probably already be behind), the program is strict in its requirements and there are plenty of difficult classes required.

Yeah, Im currently looking at 4 to 4.5 yrs because I started with algebra but it would be 5 if I wasnt going to summer school to catch up. But it seems like alot of people in my classes arent even considering it in four yrs and are just shooting for five. But my goal was always 4 so thats why I had brought this up.

4 years would perhaps be typical for a baccalaureate (Bachelor of/in Science, BS). Then about 2 years for Master of Science (MS). Then perhaps 2-4 years of PhD. Then can be some acceleration if one allows for overlap or heavy course schedule.

It also depends upon one's preparation prior to university. Some can take calculus and advanced analysis in high school, where as others must wait until university.